1. Field of the Invention
The invention relates to a knee joint orthosis with a thigh shell to be attached to the patient's thigh, a lower leg shell to be attached likewise by bandages or the like to the lower leg, and with two joint rods, said rods being located laterally opposite one another, approximately perpendicular with the leg extended, and connecting the two leg shells together with articulation, each of said rods being connected at its upper end by an upper articulation point with the thigh shell and at its lower end by a lower articulation point with the lower leg shell in such fashion that the distance between the two articulation points decreases from a maximum with the leg extended to a minimum with the knee completely flexed.
2. Description of the Prior Art
EP 0 567 673 A1 shows an embodiment wherein each of the two joint rods is made adjustable lengthwise in telescopic fashion. In addition, a device is provided for dorsal flexion of the lower leg by means of the backward displacement of the joint rods, said device being formed by a ventral elastic torsion bar guided around the lateral joint rods. Each joint rod consists of two telescoping rods guided one inside the other in telescopic fashion, said rods being connectable with one another by an inner rubber cord. The two lower articulation points of the joint rods are connected together by a dorsal shackle.
An important feature of this known orthosis lies in the fact that no mechanical joint simulating the individual knee joint mechanics is provided. Instead, the knee joint mechanics are given free rein to perform the physiological movement unimpeded. The respective midpoint of the movement, with the path of the joint axis that also differs laterally, can be adjusted depending on individual anatomical conditions between the articulation points of the joint rods. The connection of the thigh and lower leg shells prevents lifting or slipping and rubbing by using independent orthosis joint mechanics. Each shell has a cutout dorsally in the vicinity of the fossa poplitea to permit pronounced flexure of the knee until the lower leg abuts the thigh.